This invention is directed to supports utilized for making spectroscopic measurements and other studies which utilize polystyrene or other aromatic containing polymers which are derivatized in such a manner so as to maintain the spectroscopic clarity of the support.
Polystyrene is one of the most used of all polymers. It is utilized either as pure polystyrene or in conjunction with a copolymer. Further, derivatives of polystyrene are known, such as chloromethylated polystyrene.
Polystyrene and its copolymers are soluble in most of the normal organic solvents with the exception of the lower alcohols. Other solvents swell or gel polystyrene and copolymers of polystyrene. The swelling action of many solvents on polystyrene allows for the use of polystyrene as the support matrix for resins utilized for chromotography, ion exchange and the like.
Appropriate functional groups can be introduced into the aromatic rings of the polystyrene by one of two methods. The first is the actual polymerization of monomers which incorporate these functional groups. U.S. Pat. No. 3,872,067 describes a process for preparing a chloromethylated polystyrene divinyl benzene copolymer utilizing appropriate polymerization of the preformed chloromethylated polystyrene monomer.
For preparing derivatives of polymerized polystyrene. it is necessary to swell the polystyrene matrix such that pores and the like are formed in the polystyrene matrix allowing for introduction of the appropriate functional groups within the interior of the polystyrene bead or the like. U.S. Pat. No. 3,956,219 describes this process and discusses the problems with regard to the same. In this patent the polystyrene is being substituted with certain peptide functionalities which have different solvent properties compared to the polystyrene. As the patent describes, in utilizing certain solvents such as methylene chloride, the polystyrene is extended, but the peptide functionalities are not soluble in this solvent or other similar solvents. The solution of U.S. Pat. No. 3,956,219 is in the use of N-methyl-2-pyrrolidone which acts both as a swelling agent for the polystyrene and as a solvent for the peptide groups.
U.S. Pat. No. 3,860,486 describes the use of polymethylated styrene as a matrix for insolubilizing certain enzymes by reacting the chloromethyl groups with 2,5-dioxo-4 oxazolidine. The water soluble enzymes react with the oxazolidine group to insolubilize the same. This patent is characteristic of certain procedures wherein biological molecules can be manipulated by the absorption, attachment or reaction of the same with a suitable insoluble matrix such as a derivatized polymer or the like.
Both U.S. Pat. Nos. 3,974,110 and 3,995,094 discuss Freidel-Crafts substitution reactions for the introduction of chloromethyl groups onto the aromatic ring of polystyrene. In the body of U.S. Pat. No. 3,995,094 discussion is set forth as to problems with regard to solvents which can be utilized for such Freidel-Crafts modifications of polystyrene. Organic solvents such a benzene, toluene, xylene and the like themselves would undergo the halomethylation reaction and thus are not useful as solvents. The alcohols, diols and the like deactivate the normal Lewis acids utilized as catalysts in these reactions. Noted as acceptable solvents for the halomethylation of polystyrene are carbon disulfide and nitroalkanes and nitroaranes and the lower haloalkanes.
The above patents are directed to the reactions specified therein with little consideration given to the actual final use of the polystyrene article. Thus, while carbon disulfide and chloroform might be suitable for Freidel-Crafts reactions on polystyrene, they could not be utilized if a polystyrene article was to be maintained in the same physical form after the reaction as it was before the start of the reaction.
U.S. Pat. No. 4,226,958 converts polystyrene to bromopolystyrene by bromination with bromine in carbon tetrachloride. The brominated polystyrene is then further reacted in other solvents to form certain organo-arsenic derivatives of the polystyrene. Again, as with the reactions discussed above, during the bromination step utilizing carbon tetrachloride little consideration is given to maintaining certain physical properties of the polystyrene such as optical clarity, optical surfaces and the like during the reaction thereon.
Because polystyrene can be derivatized such as by the formation of chloromethylated polystyrene, and because it is a transparent solid, it has been determined that polystyrene, polystyrene plus other copolymers, or other aromatic moiety containing polymers which also are optically clear, could be useful for support mediums for certain spectroscopic studies. However, in order to so utilize these polymers for this purpose, consideration must be given to maintaining the optical clarity of these supports and preventing solvation, geling, swelling, etching, or other physical changes to the support medium during any reaction on the polystyrene itself or on subsequent derivatives of polystyrene. It is to this end that this invention is directed.